Electronic extensor



May 24, 1960 A. E. CANFORA ET AL 2,938,078

ELECTRONIC EXTENSOR Filed Aug. 10, 1956 NN NNN RPP my /M/E/Ya/Qs ARTHUR E. CANFDHA HAMM: T. Kxsxr SAMUEL SHARIN ANTI-mmf I Iauum Arrow/y United States Patent 2,938,078 ELECTRONIC EXTENSOR Filed Aug. 10, 1956, ser. No. 603,400 s claims. (ci. 11s-70) The invention relates to code signalling systems. It particularly relates to a circuit arrangement for changing the condition of signal elements included in a code character and appearing either simultaneously or sequentially over separate circuits into one where the signal elements appear serially over a single circuit for use with start- `stop apparatus.

In the operation of a code signalling system, it is often necessary that the signal elements in a code character be made available, either simultaneously or sequentially, for transmission over separate circuits to apparatus included 1n the system. All of the signal elements in a character are presented either simultaneously or sequentially to the apparatus, each signal element in the character being presented to the apparatus over a different circuit. For example, in the case of a tive-unit fixed length telegraph code character, the five signal elements in the character over tive different circuits to the apparatus. However, certain types of apparatus, for

example, a start-stop telegraph printer, are adapted to opc rate only in response to an input signal in which the signal elements in each code character included in the input signal appear serially over a single circuit in startstop fashion. The signal elements in each character must be received element after element over a single circuit by the apparatus. When it is desired to operatively connectan apparatus of the latter type in a code signalling system 1n which the signal elements in each code character are made available only as signal elements appearing either simultaneously or sequentially over separate circuits, equipment must be provided for changing the condition of the signal elements available over the separate circuits into one where the signal elements appear serially over a single circuit for transmission to the apparatus.

lCircuit arrangements for accomplishing this function are presently available in the art, and are generally defined as simultaneous or sequential to serial (Sim. or Seq-Ser.) extensors. Both electronic and mechanical extensor circuits are known. The mechanical extensor circuits are not completely satisfactory because the mechanical components included n this type of circuit create difcult mechanical maintenance problems. The electronic extensor circuits presently available require a number of vacuum tubes which are used as storage tubes and an electronic commutator to scan the storage tubes. While some of the problems encountered in using the mechanical extensor circuits are eliminated by the use of the electronic eXtensor circuits, the electronic extensor circuits tend to be bulky and awkward to handle due to the number of vacuum tubes needed, thereby adding to the problerns encountered in designing equipment including an extensor circuit of this type.

It is an object of the invention to provide an improved electronic circuit arrangement for changing the condition of signal elements included in a code character and appealing either simultaneously or sequentially over sepan rate circuits into one where the signal elements appear "serially over a single circuit.

l Another object of the invention is to provide a more compact, simpler and improved electronic extensor `eircuit by utilizing magnetic cores for functions heretofore performed by electronic equipment. p Briey, the objects of the invention are accomplished by an extensor circuit arrangementincluding magnetic core shift registers to perform functions previously per formed by electronic equipment in known extensor circuits. A signal shift register and a count shift register are included in the extensor circuit, each of the shift registers including a chain of magnetic cores. Signal elements included in a code character and appearing either simultaneously or sequentially over separate circuits are applied to certain of the magnetic cores in the signal shift register. Each signal element in the code character is applied over one of the separate ci-rcuitsto a different one of the magnetic cores of the shift register. The signal elements may be marking or spacing in nature. A marking element is generally dened as a condition of current flow, while a spacing element is generally defined as a condition of no current ow. A start-stop oscillator is connected to the signal shift register and to a signal element Shaper. The signal element shaper is connected to an output terminal of the signal shift register, and normally functions to apply a voltage to a single circuit output terminal. When all of the signal elements in a code character have been applied to the different magnetic cores, a start pulse is applied from a suitable source to the start-stop oscillator. The application of the start pulse causes the start-stop oscillator to begin operation and to produce a space pulse which is applied to the signal element Shaper. The signal element shaper is responsive to the space pulse to remove the voltage from the single circuit output terminal, and a spacing element or start pulse appears at the output terminal. I

Following the application of the space pulse to the signal element shaper, the start-stop oscillator operates to produce a series of current pulses which are applied to the signal shift register. The signal shift register is responsive to the series of current pulses to produce a train of serially appearing control signals. Each of the control signals included in the train corresponds to a signal element applied to one of the different magnetic cores of the signal shift register, and the control signals are arranged in an order corresponding to the order in which the signal elements are applied over the separate circuits to the different magnetic cores. The train of control signals is applied via the output terminal of the signal shift register to the signal element Shaper. Simultaneously with the application of each of the control signals in the train to the signal element shaper, the start-stop oscillator operates to apply a space pulse to thesignal element shaper. When a control signal corresponding to a marking element applied over one of the separate circuits to a magnetic core of the signal shift register is applied to the signal element shaper, the space pulse applied to the signal element Shaper is overridden. The signal element shaper operates in response to the control signal to apply a voltage to the single circuit output terminal,v and a marking element appears at the output terminal. When a control signal corresponding to a spacing element applied over one of the separate circuits to a magnetic core of the signal shift register is applied to the signal element shaper, the signal element shaper is responsive to the space pulse applied thereto to remove the voltage from the single circuitoutput terminal. A spacing element appears at the output terminal. In this manner, signal elements applied either simultaneously or sequentially over the separate circuits to different magnetic cores of the signal shift register are made to appear serially at the single circuit output terminal.

In addition to applying the series of current pulses to lar hysteresis loop of low coercive force.

the signal shift register, the start-stop oscillator also operates to apply a series of current pulses to the count shift register. The count shift register functions in response to the series of current pulses to produce a control pulse after the train of control signals has been applied from ,the signal shift register to the signal element shaper.

Equipment is provided which is connected to an output terminal of the count shift register and to the start-'stop oscillator. The equipment is responsive to the co-ntrol pulse to stop the further operation of the start-stop oscillator. Additional equipment is provided which is con- `nected to the output terminal of the count shift register `and to the signal element shaper. The additional equipment is responsive to the control pulse to cause the signal element shaper to apply a voltage to the single circuit output terminal. A marking condition or stop pulse appears at th'eoutput terminal. An extensor circuit arrangement is disclosed by the use of which the condition of signal ele-ments appearing either simultaneously or sequentially over separate circuits can be readily changed into one where the signal elements appear serially over a single circuit for use with start-stop apparatus.

A more detailed description of the invention follows vwith reference to the accompanying drawing, in which:

ously or sequentially, over seperate output circuits for ap- 'plicatlon to an utilization circuit.

Many examples of apparatus arranged to perform this function are known in the art. By way of example only, the eXtensor circuit of the invention could be adapted for use in association with a conversion system of the type disclosed in Patent No. 2,724,739, dated November 22, 1955, to James S. Harris for Code Conversion System.

The operation of magnetic cores and of magnetic core shift registers per se is known in the art, and therefore a detailed description thereof is unnecessary. A magnetic core is a circuit element having a substantially rectangu- Input, output and shift windings are arranged on the core. A magnetic core is capable of being magnetized to saturation in either of two directions. In one direction, a positive or active state is said to arise in which the direction of retentivity is opposite to that which would result from the application of a shift or sensing pulse to the shift winding on the core. In the second direction, a negative or inactive state lis said to arise in which the direction of retentivity is the same as that which would result from the application of a shift pulse to the shift winding on the core. A shift pulse when vapplied to a magnetic core in the active state will cause the .inactive state to appear. When a shift pulse is applied to a magnetic core already in the inactive state, no change in state will occur. A magnetic core in the active or positive state is said to contain a one,

Aand `a magnetic core in the negative or inactive state is said to contain a zero When a magnetic core is shifted from an active state to an inactive state, a voltage is induced in its output winding. A shift pulse will have no substantial eect on a magnetic core in the inactive state, and substantially no voltage will be induced inits loutput winding.

A magnetic core shift register includes a chain of magnetic cores. `If a one is stored in a rst magnetic core included in a shift register such that the core is lin an active state, the application of ashift current pulse to the shift winding on the core causes a voltage to be induced in the output winding on the core. The output winding on the rst magnetic core is connected to the input winding on a succeeding core in the chain. The voltage induced in the output winding on the rst magnetic core produces a pulse which is applied to the input winding on the next magnetic core in the chain, causing a one" to be stored in the next magnetic core. Thus, the one is transferred from the lirst magnetic core to a second magnetic core included in the shift register. Additional shift current pulses can be selectively applied to the magnetic cores in the chain of magnetic cores to cause the one" to advance coreby-core along the chain of magnetic cores included in the shift register. As a result of this action, a magnetic core shift register can be adapted to perform various functions.

Referring to Figure l, the separate output circuits of apparatus of the type described above are connected individually to the signal input terminals 10 through 14. All of the signal elements in a code character, available over the separate output circuits, may be marking elements, spacing elements or the code character may include a combination of marking and spacing elements arranged in a predetermined manner. The signal elements are applied over the separate output circuits of the apparatus to different magnetic cores in the chain of magnetic cores included in the signal shift register 15 via the signal input terminals 10 through 14. When a marking element is applied to a magnetic core in the signal shift register 15 from one of the signal input terminals 10 through 14,

the magnetic core is shifted to an active state. A one is stored in each core to which a marking element is applied. When a spacing element is applied from one of the signal input terminals 10 through 14 to one of the magnetic cores in the signal shift register 15, the magnetic core remains in an inactive state. A zero is stored in each magnetic core to which a spacing element is applied.

When all of the signal elements, whether spacing or marking in nature, have been applied to different magnetic cores in the signal shift register 15, a start pulse from an external source is applied to terminal 16. The start pulse is applied from terminal 16 to a start-stop oscil lator 17 and to the first magnetic core in the count shift register 18 over lead 19. The magnetic core in thc count shift register 18 assumes an active state having a one" stored therein. A signal element shaper 20 is connected to the signal shift register 15 over lead 21 and to the start-stop oscillator 17 over lead 22. The signal element shaper 2t) normally operates to apply a voltage to output terminal 23. The reception of the start pulse causes the start-stop oscillator 17 to begin operation. T he startstop oscillator 17 produces a series of shift current pulses which are applied over leads represented by lead 24 to the magnetic cores in the signal shift register 15 and over leads represented by lead 25 to the magnetic cores in the count shift register 18. At the same time, a space pulse is applied from the start-stop oscillator 17 over lead 22 to the signal element shaper 20. The signal element shaper 20 is responsive to the space pulse to remove the voltage from the output terminal 23 such that a spacing element or start pulse appears at the output terminal 23. The shift current pulses applied to the magnetic cores in the signal shift register 15, thereafter, cause each of the signal elements stored in the magnetic cores in the signal shift register 15, either as a one or as a zero," to be advanced out of the signal shift register .'15 and to be applied in sequence over lead 21 to the signal element shaper 20.

As each shift current pulse is applied to the magnetic cores in the signal shift register 15 over lead 24, the

start-stop oscillator 17 functions to apply a space pulse ,shaper 20 from the signal shift register 15 over lead 21 overrides the space pulse applied to the signal element Shaper 2-0 from'` the start-stop oscillator 17 over lead 22. The signal element shaper- 20 assumes its normal condition in which a voltage' or marking element is applied to the output terminal 23. When a zero, corresponding to a spacing element, is advanced out of the last magnetic ,core in the signal shift register 15, a pulse yis not applied to the signal element Shaper 20 over lead 21, The operation of the signal element` Shaper 20 is, therefore, controlled by the space pulse'appl'ied to the signal element Shaper 20 from the start-stop oscillator 17 over lead 22. The signal element Shaper 20 is operated to remove the voltage from the output terminal 23. ln this manner, the signal elements, whether marking or spacing elements, originally applied either simultaneously or sequentially via the signal input terminals through 14 to different magnetic cores in the signal shift register 15 appear in series at the output terminal 23. A voltage or marking element is applied to the output terminal 23 for each marking element originally stored as a one in a magnetic core included in the signal shift register 15. No voltage or a spacing element is applied to the output terminal 23 for each spacing element originally stored as a zero in a magnetic core in the signal shift register 15. The condition of signal elements appearing either simultaneously or sequentially at the signal input terminals 10 through 14 is changed into one where the signal elements appear serially at the output terminal 23.

As the Start-stop oscillator 17 applies the series of shift current pulses to` the magnetic cores in the signal shift register 15 over lead 24, a series of shift current pulses is also applied to the count shift` register 18 over lead 25. As a result, the one originally stored in the first magnetic core of the count shift register 18 by the reception of the start pulse is advanced core-by-core along the chain of magnetic cores vin the count shift register 18. When all of the signal elements stored, either as a one or as a zero, in the magnetic cores in the signal shift register 15 have been advanced out of the signal shift register 15 and have been applied to the signal element shaper 20 over lead 21, the one originally stored in the first magnetic core in the count shift register 18 is stored in the last or output magnetic core of the count shift register 18. The start-stop oscillator 17 applies an additional shift current pulse over lead to the output magnetic core in the count shift register 18. A pulse is produced which is applied over lead 26 to stop further operation of the start-stop oscillator 17. At the same time, the pulse is applied over lead 27 to the signal element Shaper 20, causing the signal element shaper 20 to assume itsA normal condition such that a voltage is applied to the output terminal 23. A marking element or Stop pulse appears at the output terminal 23. The extensor circuit of the invention will have at this time completed a full sequence of operation, and remains in a Standby condition until the signal elements in a Subsequent code character are applied via the signalk input terminals 10 through 14 to the signal shift register 15. The operation of the extensor circuit is, thereafter, the Same as that outlined above.

A circuit diagram of an embodiment of the invention is shown, by way of example only, in Figure 2. To assist in an understanding of the invention, voltage values have been assigned to various positive and negative terminals connected to suitable sources of potential and arranged in the circuit diagram given in Figure 2. The values, however, are given only by way of example, and can be altered to meet the requirements of a particular application without departing from the spirit of the invention. The signal shift register 15 comprises a chain of magnetic cores 30 through 39, and functions in a manner known in the art. It is believed, therefore, that a detailed description of the signal shift register 15 is unnecessary. The even numbered magnetic cores 30, 32, 34, 36 and 38 constitute a line of `Storage cores, while the odd numbered magnetic cores 31, 33, 35, 37 and 39 constitute a line of temporary storage cores. Input, output and shift windings are mounted on each of the magnetic cores 30 through 39. Electrical connections are made from each of the output windings 40 through 48 to the succeeding input windings 49 through 57, respectively, each of the connections including a pair of unidirectional iinpedances or rectifiers and a resistor. The electrical connection made from the output winding 40 on; the Storage core 30 to the input winding 49 on the temporary storage core 31 includes two impedances or rectifiers 58, 59 and a resistor 60. Rectifier 58 and resistor 60 are connected in series with the input winding 49, while the rectifier 59 is connected in shunt relation across the series combination including rectifier 58, resistor 60 and input winding 49. If a one is stored in the first storage core 30, a Shift current pulse applied to the shift windings 61 through 65 on the storage cores 30, 32, 34, 36 and 38, respectively, in a manner to be described causes a voltage to be induced in the output winding 40. The voltage induced in the output winding 40 causes a pulse to be applied to the input winding 49, and a one is stored in the temporary storage core 31. Thus, the one is transferred from the first Storage core 30 to the'first temporary storage core 31. The application of a shift current pulse to the shift windings 66 through 70 on the temporary storage cores 31, 33, 35, 37 and 39, respectively, in a manner to be described causes the one to be transferred from the temporary storage core 31 to the second storage core 32 and so on.

The rectifier 58 is properly poled so that a low impedance is presented in `the electrical connection made between the output winding 40 and the input winding r49 when a one is transferred from the storage core to the temporary storage core 31. When the one is transferred from the temporary storage core 31 to .the storage core 32, a voltage is induced in the input winding 49 and in the output winding 41 on the temporary storage core 31. Rectifier 58 and resistor 60 now present a high impedance in the electrical connection to a pulse produced by the voltage being induced in the input winding 49. Rectifier 59, shunting the output winding 40 and the input winding: 49, is properly poled to present a high impedance across t-be electrical connection made between the output winding 40 and the input winding 49 when a one is transferred from storage core 30 to fthe temporary storage core 31. When a voltage is induced in the input winding 49 lupon the transfer of the one from the ltemporary storage core 31 to the storage core 32, the rectifier 59 presents a low impedance across the electrical connection, preventing a one from being fed back to the storage core 30 from the temporary storage core 31. The circuit arrangement including rectifiers 58, 59 and resistor 6d operates to attenuate a pulse produced by voltage .being induced in the input winding 49 when a one is transferred out of the temporary storage core 31. The output winding on each magnetic core in the signal shift register 15 is connected to the input winding on the succeeding core by an electrical connection Similar to that made between the output winding 40 on storage core 30 and the input winding 49 on the temporary storage core 31, the magnetic cores 30 through 39 being connected in cascade fashion. One cycle of operation, thus, consists of pulsing first the Storage line of magnetic cores and, then, the temporary storage line of magnetic cores. A one is, in this manner, advanced one stage at the end of each cycle. This type of shift register is known in the art as a two core per bit shift register. In standby condition, .the signal shift register 15 is cleared of all information, each of .the magnetic cores 30 through 39 being held in an inactive state having a zero stored therein.

A count shift register 18 is located immediately below the signal shift register 15 in Figure 2. The count Shift register 18 is similar in operation and construction to that of the signal shift register 15, and includes a chain 'of magnetic cores 71 through 82. The odd numbered of the electrical connections made includes a pair of undirectional impedances or rectiiers and a resistor. The electrical connections are made between the magnetic coresin the count shift register 18 in the same man ner as are the electrical connections between the magnetic cores in the signal shift register 15, the magnetic cores 71 through 82 -in the count shift register 18 being arranged in cascade fashion. In standby condition, the count shift register 18 is cleared of all information, and each of the magnetic cores 70 through 82 is held in an inactive state having a zero stored therein.

It is to be understood that the invention is not limited to the use of a signal and count shift register of the particular type shown in Figure 2. Other types of shift registers may be used without departing from the spirit of the invention. For example, a single core per bit shift register is known in the art. The latter type of shift register includes a single line of storage cores. The

4function performed by the'temporary storage cores in a two core per bit shift register, as described above, is performed in a single core per bit shift register by delay circuits connected between succeeding storage cores. It will be readily apparent to those skilled in the art that the extensor circuit of the invention could be adapted for use with single core per bit shift registers rather than two core per bit shift registers, as are shown in Figure 2.

The start-stop oscillator 17 includes two monostable multivibrators 105, 106 of conventional design. Multivibrator 105 includes two triode vacuum tubes VSA, V4A. Multivibrator 106 includes two triode vacuum tubes VSB, V4B. Tubes VSA, VSB may be arranged in a duo-triode vacuum tube, as may tubes V4A, V4B. The mulivibrator 105 is arranged in a circuit which pos- Isesses a single condition of stable equilibrium. Normal- 1y, tube VSA is cut off, and tube V4A is conducting. The multivibrator 105 can be triggered into a second condition in which tube VSA is conducting, and tube V4A is cut olf. However, following a time interval determined by the values of capacitor 107 and resistors 108, 109, the multivibrator 105 will automatically revert back to the original condition or condition of stable equilibrium in which tube VSA lis cut off, and tube V4A is conducting. Similarly, multivibrator 106 is included in a circuit which .possesses a single condition of stable equilibrium .in which tube VSB is cut off, and tube V4B is conducting. Multivibrator 106 can be triggered into a second condition in which tube VSB is conducting, and tube V4B is cut off. Following a time interval determined by the values of capacitor 110 and resistors 1'11, 112, the multivibrator 106 will automatically revert back to the original condition or condition of stable equilibrium in which tube VSB is cut off, and tube V4B is conducting. Diodes V2A and VZB are connected to the plates of tubes VSA, VSB, respectively, to clamp the plates of tubes VSA, VSB to ground, preventing the potential on the plates of tubes VSA, VSB from dropping below ground potential. The term ground as used in the specication is to be understood as referring to a point of fixed reference potential.

The signal element shaper 20 includes a triode vacuum tube V6A and a bistable multivibrator 11S of conventional design. Multivibrator 11S includes two triode vacuum tubes V7A, V7B arranged in a circuit possessing two states or conditions of stable equilibrium. Tubes V7A, V7B may be arranged in a duo-triode vacuum tube. In one condition, one side or tube of the multivibrator v11S is conducting, and the other side or tube is cut oi. I nthe second condition, the tube previously cut otf is conducting, and the tube previously conducting is cut off. The circuit of the multivibrator 11S remains in either the first or second condition until some action occurs which triggers the multivibrator 11S into the opposite state or condition of stable equilibrium. Because of the sudden reversal from one condition of equilibrium to the other, this type of circuit is often referred to in the art as a flip-Bop circuit. Normally, tube V7A is conducting, and tube V7B is cut off.

A winding 114 of a polar relay 115 is included in the plate circuit of tube V7A. The second winding 116 of the polar relay 115 is included in the plate circuit of tube V7B. Polar relay 115, in addition to windings 114 and 116, includes a pair of contacts 117, 118 and an armature 119 movably mounted between the contacts 117, 118. When winding 114 is energized by the conduction of tube V7A, armature 119 is made to engage contact 117. Contact 117 is connected to the positive terminal 120 of a source of potential. An electrical path is completed from terminal 120 to an output terminal 2S including contact 117 and armature 119 of polar relay 115, and a voltage is applied to output terminal 2S for application to an utilization circuit connected to the output terminal 23, for example, a start-stop telegraph printer. When tube V7B is conducting, winding 116 of polar relay 115 is energized. Armature 119 is made to engage contact 118. As contact 118 is an open contact, no voltage is applied to the output terminal 2S. It is readily apparent, therefore that when tube V7A is conducting, a voltage or marking condition is applied to the output terminal 2S. On the other hand, when tube V7B is conducting, no voltage or a spacing condition is applied to the output terminal 2S. As pointed out above, in normal or standby condition tube V7A is conducting, and tube V7B is cut off. Therefore, during periods in which the extensor circuit of the invention remains in standby condition, a voltage or marking condition is applied to the output terminal 2S.

The embodiment of the invention shown in Figure 2 is adapted for use in association with apparatus in a code signalling system which functions to supply the signal elements in a tive-unit fixed-length code character, either simultaneously or sequentially, over separate output circuits. Each of the tive signal elements whether marking or spacing in nature, is applied via one of the signal input terminals 10 through 14 to a storage core in the signal shift register 15, which may be defined as a parallel input to serial output shift register. The first signal element is applied via signal input terminal 10 to storage core S8, the second signal element is applied via signal input terminal 11 to storage core S6 and so on. It will be assumed for purposes of description that the signal elements in the letter character A in the tive-unit telegraph code are individually presented to the storage cores S0, S2, S4, S6 and S8 in the signal shift register 15. However, the operation of the extensor circuit of the invention will follow that to be outlined upon the reception of any tive-unit character. The letter character A in the tive-unit telegraph code includes the first and second signal elements as marking and the third, fourth and fifth signal elements as spacing. The signal input terminals 10 through 14 are normally open. When a spacing element is to be applied to one of the signal input terminals 10 through 14, a ground connection is completed to that terminal. When a marking element is to be applied to one of the signal input terminals 10 through 14, an electrical path is completed from the negative terminal of a source of potential to that signal input terminal. In the example given, a negative pulse is applied via signal input terminal 10 to the input winding 121 on storage core S8. A negative pulse is also applied via signal input terminal 11 to input winding 122 on storage core S6. The storage cores S6 and S8 shift from an inactive to active state, and a one is stored in each of the cores. As no current is applied tothe input windings 12S, 124 and 9 125 on the storage cores 30, 32 and 34, respectively, the storage cores 30, 32 and 34 remain in an inactive state having a zero stored therein.

A capacitor 126, shown at the left of the drawing, is

Inormally charged over an electrical path completed from the positive terminal 127 of a source of potential and including resistors 128, 129. A further capacitor 130 is also normally charged over an electrical path completed from the positive terminal 127 and including resister 128. A few milliseconds after all of the signal elements in the code character A have been individually applied to the storage cores 30, 32, 34, 36 and 38 in the signal shift register 15, a start pulse is applied from an external source to terminal 16. The start pulse may be produced as a function of the apparatus supplying the signal elements over separate circuits to the signal shift register or by a suitable timing mechanism, many examples of which are known in the art. For example, the electronic extensor of the present invention may be adapted for use in connection with the code conversion system shown in Patent No. 2,724,739, dated November 22, 1955 and issued to James S. Harris for Code Converson System. The iive elements of the code character are applied via ve output circuits of the code converter shown in Fig. 1b of ,the reference to the storage cores of the signal shift register 15. The terminal 16 is connected to the extensor control also shown in Figure 1b of the reference. As described in the reference, the extensor control produces a transfer pulse corresponding to the start pulse referred to herein for application to terminal 16 at a time following the appearance of the elements of the code character in the output circuits of the code converter, and so on. The start pulse is, in the example given, in the form of a negative going pulse (or transfer pulse), resulting in the terminal 16 becoming negative with respect to the charged condition of the capacitors 130, 126. In other applications, a suitable timing mechanism may be provided to complete a simple ground connection to the terminal 16. The application of the start pulse to terminal 16 causes capacitor 130 to discharge, and a pulse is applied to the input windings 131, 132 on the storage core 71 in the count shift register 1-8. The storage core 71 shifts from an inactive to active state, and a one is stored therein. At the same time, capacitor 126 discharges, causing a neon tube 133 to re. When the neon tube 133 is fired, a negative pulse is produced which is applied to the plate of tube V3A over an electrical path including a differentiating circuit, comprising capacitor 134 and resistor 135, and lead 136.

As pointed out above, the monostable multivibrator 105 is arranged in a circuit possessing a single state or condition of stable equilibrium in which tube V3A is cut off, and tube V4A is conducting. When the negative pulse is applied to the plate of tube V3A, the multivibrator 105 is triggered to a condition in which tube V3A is conducting, and tube V4A is cut off. negative, space pulse is applied from the plate of tube V3A to the cathode of tube V7B in the bistable multivibrator 113 over an electrical path including lead 22 and coupling capacitor 137. Multivibrator 113 is normally in 4a condition of stable equilibrium in which V7B is cut off. The negative pulse applied to the cathode of tube V7B triggers the multivibrator 113 to its other state of stable equilibrium in which tube V7A is cut olf, and tube V7B is conducting. The winding 116 of polar relay 118 is energized, causing armature k119 to engage contact 118. As contact 118 is open, no voltage ora spacing condition is applied to the output terminal 23. The spacing element appearing at the output terminal 23 operates as a start pulse which can function to begin the operation of an utilization circuit connected to the terminal 23.

When tube V4A is cut off, from the plate of tube V4A triode vacuum tube VlB lead 138 and coupling a positive pulse is applied to the `control grid of a over an electricalpath including capacitor 139. rIlube V'1B be` tube V7A is conducting, and tube 'comes' conducting.V g A shift-current;

pulsel is applied over lead 140 t the shift windings 141 through 146 on the respective temporary storage cores 72, 74, 76, 78, and 82 in the count shift register 18 and to the shift windings 66 through on the `respective temporary storage cores 31, 33, 35,137 and 39 in the signal shift register 15. As all of the temporary storage cores in the signal shift register 15 and inthe count shift register 18 are at this time in an inactive state, the first shift current pulse produced bythe operation of the startstop oscillator 17 will have no affect on theinformation stored in the respective shift registers. At the end of, a time interval determined bythe values of capacitor 107 and resistors l108 andV 109, for example, a time interval of eleven milliseconds duration, the multivibrator automatically reverts back to its singlecondition of stable equilibrium in which tube VSA is out oit, and tube V4A is conducting. A negative pulse is Yapplied from the plate of tube V4A to the plate of tube V3B. Multivibrator 106 is arranged in a' circuit possessing a single condition of's'table equilibrium in `which tube V3B is cut olf, and tube V4B is conducting'. The negative pulse applied to the plate oftub'eVSB `triggers the multivibrator 106 into a condition in which tube V3B is conducting, and tube V4B is cut olf. A positive pulse is applied from the plate of tube V4B to the control grid of a triode vacuum tube VIA over an electrical path including lead 150, lead 151 and a coupling `capacitor 152. Tube V1A becomes conducting. A shift current pulse is applied over a lead 1153 to the shift windings 154 through 159 on the respective storage cores 71, 73', 75, 77, 79 and 81 in the count shift register 18 and to the shift windings 61 through 65 on the respective storage cores 30, 32, 34, 36 and 38 in the signal shift register 15. The onef stored in storage core 71 is transferred to the temporary storage core 72 in the count shift register 18. At the same time, the one stored -in the storage core 36 is transferred to the temporary storage core 37, and the one stored in the storage core 38 is transferred to the temporary storage core 39 in the signal shift register 15. Each one stored in a storage core in the signal shift register 15 is advanced to a succeeding temporary storage core, and the one originally stored in the input storage core 71 Vin the count shift register 18 is advanced to the temporary storage core 72.

At the end of a time interval determined by the values of capacitor and resistors `1'11, 112, for example, a time interval of eleven milliseconds duration, the multivibrator 106 automatically reverts back to its single condition of stable equilibrium in which tube V3B is cut off, and tube V4B is conducting'. A negative pulse is applied from the plate of tube V4B to the plate of tube V3A over an electrical path including lead 150, -a Idilferentiating circuit, comprising capacitor 160 and resistor 161, and lead 162. Multivibrator 105 is triggered to the condition in which tube V3A is conducting, and tube V4A is cut olf. As previously described, a vpositive pulse is applied from the plate of tube V4A to the control grid of tube V1B over lead 138. Tube V1B conducts, and a shift current pulse is Iapplied over lead to the shift windings 141 through 146 on the respective temporary storage cores 72, 74, 76, 78, 80 and 82 in the count shift register 18 and to the shift windings 66 through 70 on the respective temporary storage cores 31, 33, 35, 37 and 39 in the signal shift register 15. The one stored in the temporary storage core 72 is transferred to the storage core 73 in the count shift register 18. The one stored in the temporary storage core 37 is transferred to thestorage core 38, vand the one stored in the temporary storage core 39 is advanced out of the signal shift register 15. A voltage is induced in the output winding 163 on the temporary storage core 39, and a positive pulse is applied to the control grid of a triode vacuum tube V6A over an electrical path including an integrating circuit, comprising capacitor 164 and resistor 165, which operates to widenzthepulse. TubeV-A be@ 11 comes conducting, and la negative pulse is applied from the plate of tube V6A to the plate of tube V7A in the multivibrator 113.

When tube V3A in multivibrator 105 becomes cond-ucting, a negative, space pulse is again applied from the plate of tube V3A to the cathode of tube V7B over lead 22. It will be remembered that multivibrator 113 is, at this time, in the condition of stable equilibrium in which tube V7A is cut olf, and tube V7B is conducting. Normally, the application of the space pulse to the cathode of tube V7B tends to maintain the multivibrator l113 in this condition of stable equilibrium. However, the negative pulse applied to the plate of tube V7A from the plate of tube V6A is wider than the space pulse applied to the cathode of tube V7B. The negative pulse applied to the plate of tube V7A overrides the space pulse and triggers the multivibrator 113 into its other condition of stable equilibrium. Tlbe V7A becomes conducting, driving the control grid of tube V7B negative. `Tube V7B is cut off. Winding 114 of polar relay 115 is energized, causing armature 119 to engage contact 117. An electrical path is completed from the positive terminal 120 to the output terminal 23, and a voltage or marking element is applied to the output terminal 23. The marking element originally stored as a one in the storage core 38 in the signal shift register 15 is in this manner the iirst signal element to appear at the output terminal 23 for application to an utilization circuit.

At the end of the time interval determined by the values of capacitor 107 and resistors 108, 109, multivibrator 105 automatically reverts back to its single condition of stable equilibrium in which tube V3A is cut off, and tube V4A is conducting. A negative pulse is applied to the plate of tube V3B from the plate of tube V4A, and multivibrator 106 is triggered into the condition in which tube V3B is conducting, and tube V4B is cut off. A positive pulse is applied to the control grid of tube V1A from the plate of tube V4B over lead 150 and lead -1. Tube V1A becomes conducting. A shift current pulse is applied over lead 153 to the shift windings 154 through 159 on the respective storage cores 71, 73, 75, 77, 79, and 81 in the count shift register 18 and to the shift windings 61 through 65 on the respective storage cores 30, 32, 34, 36 and 38 in the signal shift register 15. The one stored in the storage core 73 is transferred to the temporary storage core 74 in the count shift register 18. The one stored in the storage core 38 is transferred to the temporary storage core 39 in the signal shift register 15.

At the end of the time interval determined by the values of capacitor 110 and resistors 111, 112, multivibrator 106 automatically reverts back to its single condition of stable equilibrium in which tube V3B is cut oif, and tube V4B is conducting. A negative pulse is applied from the plate of tube V4B to the plate of tube V3A over lead 150 and lead 162. Multivibrator 105 is triggered to the condition in which tube V3A is conducting, and tube V4A is cut oi. A space pulse is applied from the plate of tube V3A to the cathode of tube V7B over lead 22. At the same time, a positive pulse is applied from the plate of tube V4A to the control grid of tube V1B over lead 138. Tube V1B becomes conducting. A shift current pulse is applied over lead 140 to the shift windings 141 through 146 on the respective temporary storage cores 72, 74, 76, 78, 80 and 82 in the count shift register 18 and to the shift windings 66 through 70 on the respective temporary storage cores 31, 33, 35, 37

and 39 in the signal shift register 15. The one stored in the temporary storage core 74 is transferred to the storage core 75 in thecount shift register 18. The one stored in the temporary storage core 39 is advanced out of the signal shift register 15. A voltage is induced in the output winding 163 on the temporary storage vcore 39, and a positive pulse is applied to thercontrol grid of tube V6A in the manner described above. Tube V6A l2 conducts, and a negative pulse is applied from the plate of tube V6A to the plate of tube V7A in the multivibrator 113.

The negative pulse applied to the plate of tube V7A overrides the space pulse applied to the cathode of tube V7B. Multivibrator 113 remains in the condition of stable equilibrium in which tube V7A is conducting, and tube V7B is cut olf. An electrical path continues to be completed from the positive terminal to the output terminal 23 including contact 117 and armature 119 of polar relay 115. A voltage or marking element is applied to the output terminal 23. The marking element originally stored as a one in storage core 36 in the signal shift register 15, therefore, appears by the operation of the signal element Shaper 20 as the second signal element presented to the output terminal 23 for application to an utilization circuit.

The start-stop oscillator 17 continues to operate in the manner described above. When multivibrator 105 automatically reverts back to its single condition of stable equilibrium, multivibrator 106 is triggered. A positive pulse is applied from the plate of tube V4B to the control grid of tube V1A over leads 150, 151. Tube V1A becomes conducting, causing a shift current pulse to be applied over lead 153 to the shift windings 154 through 159 on the respective storage cores 71, 73, 75, 77, 79 and 81 in the count shift register 18 and to the shift windings 61 through 65 on the respective storage cores 30, 32, 34, 36 and 38 in the Signal shift register 15. The one stored in storage core 75 is transferred to the temporary storage core 76 in the count shift register 18. It was assumed that marking elements were applied to the first two storage cores 38, 36, reading from right to left,

and that spacing elements were applied to the remaining three storage cores 34, 32 and 30 in the signal shift register 15. The one originally stored in the storage core 38 and in the storage core 36 have at this time been advanced out of the signal shift register 15 by the action outlined above. All of the magnetic cores in the signal shift register 15 are now, therefore, in an inactive state having a zero stored therein. As a one" is not available for transfer from any one of the storage cores 30, 32, 34, 36 or 38, the temporary storage cores 31, 33, 35, 37 and 39 all remain in an inactive state upon the application of the shift current pulse to the shift windings 61 through 65 on the res ective store cores 30, 32, 34, 36 and 38 in the signal shift register When multivibrator 106 automatically reverts back to its single condition of stable equilibrium, multivibrator 105 is triggered. A positive pulse is applied from the plate of tube V4A to the control grid of tube VIB over lead 138, and tube V1B becomes conducting. A shift current pulse is applied over lead to the shift windings 141 through 146 on the respective temporary storage cores 72, 74, 76, 78, 80 and 82 in the count shift register 18 and to the shift windings 66 through 70 on the respective temporary storage cores 31, 33, 35, 37 and 39 in the signal shift register 15. The one stored in the temporary storage core 76 is transferred to the storage core 77 in the count shift register 18. As a zero is stored in the temporary storage core 39 in the signal shift register 15, no voltage is induced in the output winding 163 on the temporary storage core 39. Tube V6A remains cut off, and a negative pulse is not applied from the plate of tube V6A to the plate of tube V7A.

When multivibrator 105 is triggered, a negative, space pulse is applied from the plate of tube V3A to the cathode of tube V7B over lead 22. Multivibrator 113 is triggered, and assumes its other condition of stable equilibrium in which tube V7A is cut olf, and tube V7B is conducting. Winding 116 of polar relay 115 is energized, causing armature 119 to engage contact 118. As contact 118 is an open contact, no voltage or a spacing element is applied to the output terminal 23. The

the storage core 79 in the count shift register 18. As

a zero is stored in the temporary storage core 39 in the signal shift register 15, no voltage is induced in the output winding 163. Tube `V6A remains cut olf, and a negative pulse is not applied to the plate of tube V7A. The space pulse applied from the plate of tube V3A to the cathode of tube V7B over lead 22 causes the multivibrator 113 to remain in its conditionof stable equilibrium in which tube V7A is cut off, and tube V7B is conducting. Armature 119 continues to engage contact 11S of polar relay 115. No voltage or a spacing element is applied to the output terminal 23, and the spacing element originally stored as a zero in the storage core 32 in the signal shift register 15 appears as the fourth signal element at the output terminal '23 for application to an utilization circuit. In the next operation of the Start-stop oscillator 17, multivibrator 106 is triggered, and the one stored in the storage core 79 is transferred to the temporary storage core 80 in the count shift register 18. Multivbrator 105 is then triggered, and the one stored in the temporary storage core 80 is transferred to the storage core 81 in the count shift register 18. A space pulse is applied from the plate of tube V3A to the cathode of tube V7B over lead 22, and the multivibrator I113 remains in its condition of stable equilibrium in which tube V7A is cut off, and tube V7B is conducting. No voltage or a spacing element is applied to the output terminal '23, and the spacing element originally stored as a zero in the storage core 30 in the signal shift register 15 appears as the fifth signal element at the output terminal 23. Thus, the tive signal elements applied to the storage cores 30, 32, 34, 36 and 38 in the signal shift register 15 will have appeared in series at the output terminal 23. v

It may be seen, therefore, that a signal element appears at the output terminal 23 following each complete cycle of operation of the start-stop oscillator 17. The startstop oscillator 17 is operated to rst supply a shift current pulse to the storage cores 30, 32, 34, 36 and 38 and then to the temporary storage cores 31, 33, 35, 37 and 39 in the signal shift register 15. The duration of a signal element appearing at the output terminal 23 is, therefore, determined by the time required for the multivibrator 105 to revert back to its single condition of stable equilibrium following the triggering thereof plus the time required for the multivibrator 106 to revert back to its single condition of stable equilibrium following the triggering thereof. It has been stated, by Way of example, that the time required for this action by each of the multivibrators 105, 106 may be eleven milliseconds. Following the example given, a signal element appearing at the output terminal 23 is of approximately twentytwo milliseconds duration.

Following the appearance of the last or fth signal element at the output terminal 23, multivibrator 106 is triggered. The one stored in the storage core 81 is transferred to the temporary storage core 82 in the count shift register 18. Multivbrator 105 is then triggered, and the one stored in the temporary storage core 82 is advanced out of the count shift register 18. A voltage is induced in the output winding 166 on the temporary storage core 82. The winding 166 is mounted on the temporary storage core 82 such that a negative pulse is produced and applied to the control grid of a triode vac-l uum tube V6B over an electrical path including an integrating circuit, comprising -a capacitor 167 'and a re'sist'ot' 168. Tube V6B is normally conducting, and is cut off upon the application of the negative pulse to the control grid thereof. The negative pulse produced by the voltage induced in the output winding 166 on the temporary storage core 82 is widened by the integrating circuit and appears as a positive pulse at the plate of tube V6B.

The positive pulse is applied from the plate of tube V6B to the control grid of tube V6A. Tube V6A becomes conducting, and a negative pulse is applied from the plate of tube V6A to theplate of tube V7A. When multivibrator is triggered, a space pulse is applied to the cathode of tube V7B from the plate of tube V3A over lead 22. The negative pulse applied to the plate of tube V7A overrides the space pulse, and causes the multivibrator 113 to be 'triggered into its condition of stable equilibrium in which tube V7A is conducting, and tube V7B is cut ot. Winding 114 of polar relay 115 is energized, causing armature 119 to engage contact 117. An electrical path is completed from the positive terminal 120 to the output terminal 23, and a voltage or a marking condition is applied to the output terminal 23 for application to an utilization circuit. The marking condition appearing at the output terminal 23 can be used as a stop pulse to terminate the operation of an utilizatiton circuit connected to the output terminal 23. If the negative pulse were not applied to the plate of tube V7A, the space pulse applied to the cathode of tube V7B from the plate of tube V3A over lead 22 by the last triggering of multivibrator 105 would cause multivibrator 113 to assume or remain in its condition of stable equilibrium vin which tube V7A is cut off, and tube V7B is conducting. A spacing element or condition would continue to appear at the output terminal 23, and an utilization circuit, for example, a start-stop telegraph printer, connected to the output terminal 23 would be left in a free-running condition.

The positive pulse appearing at the plate of tube V6B is also applied from the plate of tube V6B to the control grid of a triode vacuum tube VSA over an electrical path including a coupling capacitor 169 and lead 26. Tube VSA is normally conducting, and functions as a cathode follower stage to supply a negative biasing voltage to the cathodes of tubes V3A, V3B. When the positive pulse is applied to the control grid of tube VSA, the cathode of tube VSA becomes more positive. As a result, the voltage applied to the cathodes of tubes V3A, V3B becomes more positive. Multivbrator 106 is in its single condition of stable equilibrium in which tube V3B is cut off, and tube V4B is conducting. Multivbrator 105, however, will have just been triggered to the condition in which tube V3A is conducting, and tube V4A is cut off. The positive voltage applied to the cathode of tube V3A from the cathode of tube V5A causes the cathode of tube V3A to become more positive than the control grid of tube V3A, and tube V3A is cut off. When tube V3A is cut off, tube V4A becomes conducting. As tube V4A becomes conducting a short time after having been cut off by the triggering of multivibrator 105, a narrow positive pulse with a sharp negative transition appears at the plate of tube V4A. The narrow positive pulse is applied to the plate of tube path including a differentiating circuit, comprising resistor 170 and capacitor 171. The positive pulse applied to the plate of tube V3A is of insufficient width and magnitude to trigger multivibrator 106. In addition, the positive voltage applied to the cathode of tube V3B from the cathode of tube VSA serves to prevent tube V3B from conducting upon the application of the narrow positive pulse to the plate of tube V3B. The start-stop oscillator 17 is, therefore, stopped from further operation.

The extensor circuit of the invention will have, at this time, completed a full sequence of operation. The startstop oscillator 17 is returned to its standby condition in V3B over an electrical which tubes VSA, VSB are cut off, and in which tubes V4A, V4B are conducting. The signal element shaper circuit is operated to apply a voltage or marking condition to the output terminal 23. All of the magnetic cores in the signal shift register 15 and in the count shift register 18 are in an inactive state having a zero stored therein. The extensor circuit will remain in this condition until the signal elements `in a subsequent code character are applied to the Storage cores 30, 32, 34, 36 and 38 in the signal shift register 15. At that time, the operation of the extensor circuit will follow that outlined above. While the operation of the invention has been described in connection with a five-unit code character, it is to be understood that the invention is not limited vto this application. The circuit arrangement shown in Figure 2 may be adapted to operate in response to a code character including more than tive-units by simply adding the necessary number of magnetic cores to the chain of magnetic cores in the signal shift register 15 and in the count shift register 18. On the other hand, the' circuit arrangement may be adapted to operate in response to a code character including less than fiveunits by removing the necessary number of magnetic cores from the chains of magnetic cores in the signal shift register 15 and in the count shift register 18.

A Sequential or simultaneous to serial extensor circuit is diclosed which is both compact in construction and simple in operation. As each one is advanced out of the signal shift register 15, a marking element is applied to the output terminal 23 by the operation of the signal element shaper 20. For each zero advanced out of the signal shift register 15, the signal element shaper 20 operates in response to the space pulse produced by the start-stop oscillator 17 to cause a spacing element to appear at the output terminal 23. The signal elements in a code character applied to the signal shift register 15 are, in this manner, made to appear in series at the single output terminal 23 for application to a utilization circuit in start-stop fashion.

What is claimed is:

l. In combination, a chain of magnetic cores, separate input circuits connected and adapted to supply a plurality of signal elements of different nature individually to different magnetic cores in said chain to cause each of said different magnetic cores to assume one of two possible electrical conditions according to the nature of the signal element applied thereto, an output terminal, a signal element shaper connected to said terminal and to the last magnetic core in said chain and arranged to normally supply an output signal to said terminal, a normally inoperative oscillator connected to said magnetic cores and to said signal element shaper and arranged to be operated to produce a first space pulse and a train of advance pulses upon a Start pulse being applied to said oscillator after all of said signal elements are applied to said different magnetic cores, means connected between said oscillator and said signal element shaper to apply said first space pulse from said oscillator to said signal element Shaper to cause said signal element shaper to remove said output signal from said terminal, means connected between said oscillator and said magnetic cores to apply said advance pulses to said magnetic cores to cause said electrical conditions to be advanced serially from magnetic core to magnetic core through said chain and to be applied as corresponding serially appearing control signals from said last magnetic core to said signal element shaper following the application of said first space pulse to said signal element shaper, said oscillator being arranged upon the operation thereof to apply an additional space pulse by said first-mentioned means to said signal element shaper upon the application of each of said control signals to said signal element shaper, said signal element shaper being responsive to each of said control signals corresponding to one of said electrical conditions and to said additional space pulse to apply said output signal to said terminal and responsive to each of said control signals corresponding to the other one of said electrical conditions and said additional space pulse to remove said output signal from said terminal.

2. In combination, a chain of magnetic cores, sepa rate input circuits connected and adapted to supply a plurality of signal elements of different nature individually to'ditierent magnetic cores in said chain to cause each of said different magnetic cores to assume one of two possible electrical conditions according to the nature of the signal element applied thereto, an output terminal, a signal element Shaper connected to said terminal and to the last magnetic core in said chain and arranged to normally supply an output signal to said terminal, a normally inoperative oscillator connected to said magnetic cores and to said signal element shaper and arranged to be operated to produce a first space pulse and a train of advance pulses upon a start pulse being applied to said oscillator after all of said signal elements are applied to said different magnetic cores, means connected between said oscillator and said signal element shaper to apply said first space pulse from said oscillator to said signal element shaper to cause said signal element shaper to remove said output signal from said terminal, means connected between said oscillator and said magnetic cores to apply said advance pulses to said magnetic cores to cause said electrical conditions to be advanced serially from magnetic core to magnetic core through said chain and to be applied as corresponding serially appearing control signals from said last magnetic core to said signal element shaper following the application of said first space pulse to said signal element shaper, said oscillator being arranged upon the operation thereof to apply an additional space pulse by said first-mentioned means to said signal element shaper upon the application of each of said control signals to said signal element shaper, said signal element shaper being responsive to each of said control signals corresponding to one of said electrical conditions and to said additional space pulse to apply said output signal to said terminal and responsive to each of said control signals corresponding to the other one of said electrical conditions and said additional space pulse to remove said output signal from said terminal, a pulse producing means connected to said oscil- Vlator and responsive to said advance pulses to produce a control pulse following the application of Said train of control signals to said signal element shaper, and means connected between said pulse producing means and said oscillator and responsive to said control pulse to render said oscillator inoperative.

3. A combination as claimed in claim 2 and wherein said oscillator includes first and second monostable multivibrators connected in series and arranged in a loop circuit for sequential operation, said signal element shaper including a bistable multivibrator adapted to be operated in one of its stable states in response to each of said control signals corresponding to one of said electrical conditions and said additional space pulse and in its other stable state in response to each of said control signals corresponding to the other of said electrical conditions and said additional space pulse.

4. In combination, a chain of magnetic cores, separate input circuits connected and adapted to supply a plurality of signal elements of different nature individually to different magnetic cores in said chain to cause eacn of said different magnetic cores to assume one of two possible electrical conditions according to the nature cf the signal element applied thereto, an output terminal, a signal element shaper connected to said terminal and to the last magnetic core in said chain and arranged to normally supply an -output Signal to said terminal, a normally inoperative oscillator connected to said magnetic cores and t0 Said signal element shaper and arranged to be operated to produce a first space pulse and a train of advance pulses upon a start pulse being applied to said oscillator after all of said signal elements are applied to said different magnetic cores, means connected between said oscillator and said signal element shaper to apply said rst space pulse from said oscillator to said signal element Shaper to cause said signal element shaper to remove said loutput signal from said terminal, means connected between said oscillator and said magnetic cores to apply said advance pulses to said magnetic cores to cause said electrical conditions to be advanced serially from l magnetic core to magnetic core through said chain and to be applied as corresponding serially appearing control signals from said last magnetic core to said signal element shaper following the application of said first space pulse to said signal element Shaper, said oscillator being arranged upon the operation thereof to apply an additional space pulse by said rst-mentioned means to said signal element Shaper upon the application of each of said control signals to said signal element shaper, said signal element Shaper being responsive to each of said control signals corresponding to one of said electrical conditions and to said additional space pulse to apply said output signal to said terminal and responsive to each of said control signals corresponding to the other one of said electrical conditions and said additional space pulse to remove said output signal from said terminal, a pulse producing means connected to said oscillator and responsive to said advance pulses to produce a control pulse following the application of said train of control signals to said signal element Shaper, means connected between said pulse producing means and said oscillator responsive to said control pulse to render said oscillator inoperative, and a further means connected between said pulse producing means and said signal element shaper responsive to said control pulse to cause said signal element shaper to apply said output signal to said terminal.

5. In combination, a chain of magnetic cores, separate input circuits connected and adapted to supply a plurality vof signal elements of different nature individually to different magnetic cores in said chain to cause each of said different magnetic cores to assume one of two possible electrical conditions according to the nature of the signal element applied thereto, an output terminal, a bistable multivibrator connected to said terminal and at one side to the last magnetic core in said chain and arranged to be normally in one of its stable states to apply an output signal to said terminal, a normally inoperative start-stop oscillator including a pair of monostable multivibrators connected in series and arranged in a loop circuit for sequential operation connected to said magnetic cores and to the other side of said bistable multivibrator,

said oscillator being arranged to be operated to produce a first space pulse and a train of advance pulses upon a start pulse being applied to said oscillator after all of said signal elements are applied to said dilerent magnetic cores, means connected between said voscillator and said bistable multivibrator to apply said first space pulse from said oscillator to said other side of said bistable multivibrator to cause said bistable multivibrator to assume its other stable state and to remove said output signal from said terminal, means connected between said oscillator and said magnetic cores to apply said train of advance pulses to said magnetic cores to cause said electrical conditions to lbe advanced serially from magnetic core to magnetic core through said chain and to be applied as corresponding serially appearing control signals from said last magnetic core `to said one side of said bistable multivibrator following the application of said first space pulse to said other side of said bistable multivibrator, said oscillator being arranged upon the operation thereof to apply by said first-mentioned means an additional space pulse to said other side of said bistable multivibrator upon the application of each of said control signals to said one side of said bistable multivibrator, said bistable multivibrator being responsive to each of said control signals corresponding to one of said electrical conditions and to said additional space pulse to assume said `one stable state to apply said output signal to said terminal, said bistable multivibrator being responsive to each of said control signals corresponding to the other of said electrical conditions and to said additional space pulse to assume said other stable state to remove said output signal from said terminal, a second chain of magnetic cores connected to said oscillator andresponsive to said advance pulses to produce a control pulse following the application of said control signals to said bistable multivibrator, electronic switching means connected between said second chain of magnetic cores and said oscillator responsive to said control pulse to render said oscillator inoperative, and means to apply said control pulse from said second chain of magnetic cores to said one side of said bistable multivibrator to cause said bistable multivibrator to assume said one stable state to apply said output signal to said terminal.

References Cited in the tile of this patent UNITED STATES PATENTS Mumma July 9, 1946 Browne Sept. 29, 1953 OTHER REFERENCES Electronics, Computers, 

